JP2014221605A - Weight detection sensor of seat device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a weight detection sensor capable of correctly detecting weight of an occupant, in the case where relative angular displacement occurs at a floor side fixing member or a seat side fixing member.SOLUTION: The weight detection sensor of a seat device for a vehicle includes: deformation detection element units each having a first deformation detection element and a third deformation detection element disposed between an end part and a central part of a deformed body, at positions where compressive deformation occurs at the deformed body when weight of an occupant is applied, and a second deformation detection element and a fourth deformation detection element disposed at positions where tensile deformation occurs at the deformed body; a connection member fixed to the central part of the deformed body and a seat side fixing member; and a bridge circuit in which the respective deformation detection elements are made to be variable resistance. The deformation detection element units are disposed so as to be a pair in at least one of front-to-back and left-to-right directions of a seat for a vehicle, so that first end parts being a pair are located at positions symmetrical in the direction forming the pair.

Description

  The present invention relates to a weight detection sensor for a vehicle seat device that accurately detects an occupant seated on a vehicle seat.

  Conventionally, in order to improve the performance of various safety devices such as seat belts and airbags installed in automobiles, there is a technique for controlling the operation of these safety devices in accordance with the weight of an occupant seated on the seat. For example, when an occupant is seated on a seat and does not wear a seat belt, a warning lamp “not seat belt” is generally displayed after the seating is detected. Also, North American legislation stipulates that airbags should be deployed in the event of an accident when an adult is seated in the passenger seat. Thus, it is extremely important in terms of safety to detect and correctly determine the weight of the passenger.

  According to Patent Document 1 as a conventional technique, two fixing holes provided on both ends of a long plate and fixed to one member, respectively, and arranged between the two fixing holes and fixed to the other member. A sensor substrate (straining body) includes a detection hole and at least one strain detection element attached to the upper surface of the long plate between the fixing hole and the detection hole, and is press-fitted into each fixing hole of the sensor substrate. A strain sensor having a fixed member and a detection member (connecting member) press-fitted into the detection hole of the sensor substrate is described. An external force is applied to the end portion of the detection member that contacts the sensor substrate, and a reaction force is applied to the end portions of the two fixing members that contact the sensor substrate, and a strain based on the external force and the reaction force is applied to the sensor substrate. Detection is performed by the worn strain detection element.

  In the strain sensor disclosed in Patent Document 1, a plurality of strain detection elements are arranged side by side on a central straight line in the longitudinal direction of a sensor substrate (a strain generating body). These strain detection elements can detect a load value or the like by strain due to tension or compression in one direction (direction parallel to the gauge length). Therefore, the strain sensor of Patent Document 1 is interposed between the vehicle seat and the floor side fixing member, and the detection hole is connected to the seat frame (seat side fixing member) and the fixing hole is connected to the floor side fixing member. Thus, when the occupant's load from above and below applied to the vehicle seat is transmitted to the sensor board, it is possible to detect the occupant's weight from the strain of the strain detection element arranged on the sensor board. It is.

  However, when the occupant is seated on the seat, the hip point at which the occupant's weight is loaded is away from the position of the seat frame on which the sensor board is placed. Bending occurs. And between this seat side fixing member (member of the seat frame extending in the front-rear direction) and the floor side fixing member corresponding to both ends of the seat frame due to this bending, in the front-rear direction with respect to the floor side fixing member A relative angular displacement occurs in such a direction that the extending seat-side fixing member falls inward in the vehicle width direction. For this reason, a sensor board that detects the occupant's load as a load generated in the up-down direction has a load error in a direction that falls to the side (inner side) of the seat frame in the lateral direction of bending. There is a possibility that the load error in the direction of falling inward in the vehicle width direction due to the seating load affects the strain detection element of the sensor board and cannot accurately detect the weight of the occupant.

  In addition, the floor side fixing member and the seat frame on which the sensor board is arranged are rectangular rigid bodies, but the floor side fixing member and the seat frame are attached to the vehicle by a sudden brake or the like separately from the load from the up and down direction by the occupant. When a biased external force that causes deformation is applied, the front and rear sides of the vehicle floor are twisted in opposite directions around a central axis OW that passes through the center of the seat frame in the front-rear direction and extends in the left-right direction. Tend to elastically deform (see FIG. 15). As a result, when a moment load is applied that twists the floor side fixing member or the seat frame in the opposite directions around the central axis OW extending in the left-right direction, the floor side fixing member and the seat frame are There may be a relative angular displacement around the central axis OW extending in the left-right direction. Since this relative angular displacement affects the strain of the strain detection element that detects the weight, there is a possibility that the weight of the occupant cannot be detected accurately.

  Therefore, conventionally, a strain detection element to the sensor board is connected to the Wheatstone bridge circuit as a variable resistor, and as shown in FIG. 32, the four front, rear, left and right FL, RL, FR, RR of the upper rail of one vehicle seat are connected. By using a weight detection sensor in which two strain detection element units SU each including the first to fourth strain detection elements SG1 to SG4 are used for the strain generating body 20 disposed, the above two types of relative By canceling the influence of the load error due to the angular displacement between the strain detection elements SG1 to SG4 of the eight strain detection element units SU, only the weight of the occupant can be detected accurately.

JP 2003-83707 A

  However, in addition to being able to accurately detect the occupant's load without being affected by the load error due to the relative angular displacement between the floor side fixing member and the seat frame, it is possible to reduce the number of parts and reduce the cost. There was a need for a new weight detection sensor.

  The present invention has been made in view of the related problems, and accurately detects the weight of an occupant even when a load error due to relative angular displacement occurs between the floor-side fixing member and the seat frame. It is possible to provide a weight detection sensor for a vehicle seat that can reduce the cost by reducing the number of parts.

  In order to solve the above-described problem, the structural feature of the invention according to claim 1 is that a seat-side fixing member that fixes a vehicle seat is connected to the floor-side fixing member that is fixed to the floor of the vehicle. A weight detection sensor for a vehicle seat device that measures a load of an occupant seated on the vehicle seat, wherein the floor side fixing member and the seat side fixing Extending in the front-rear direction of the vehicle seat with a predetermined gap from each of the mounting surfaces formed on one of the members and arranged on the front and rear fixing portions of the vehicle seat A strain member fixed at both ends, a connecting member fixed in the vertical direction to the center of each strain member and fixed to the other of the floor side fixing member and the seat side fixing member, Weight is loaded Sometimes, between the first end portion and the central portion of the strain generating body, at positions where compressive strain is generated on the surface of the strain generating body, opposite to each other across the longitudinal center line of the strain generating body When the weight of the occupant is loaded, the first strain detecting element and the third strain detecting element arranged so as to be between the first end portion and the central portion of the strain generating body. A strain detecting element having a second strain detecting element and a fourth strain detecting element, which are arranged to be opposite to each other across the center line in the front-rear direction of the strain generating body at a position where tensile strain occurs on the surface of the body The unit, the first strain detection element, and the third strain detection element are arranged on opposite sides, and the second strain detection element and the fourth strain detection element are arranged on opposite sides, and each is variable. A Wheatstone bridge circuit as a resistor, and the strain detection element unit Wherein it becomes longitudinal and lateral of the at least one pair of the vehicle seat, and said first end portion serving as the pair is by disposing so as to be symmetrical positions in the direction to be the pair.

  The structural feature of the invention according to claim 2 is that, in the strain generating body fixed to the mounting surface disposed on the front fixing portion on at least one of the left side and the right side of the vehicle seat, The first end portion of the strain body is disposed so as to be one of the front end portion and the rear end portion of the strain generating body, and at least one of the left side and the right side of the vehicle seat. In the strain generating body fixed to the mounting surface disposed on the fixing portion on the rear side, the first end of the strain generating body includes an end on the front side and an end on the rear side of the strain generating body. It is set as the weight detection sensor of the vehicle seat apparatus of Claim 1 arrange | positioned so that it may become any one edge part.

  The structural feature of the invention according to claim 3 is that the strain generating body is fixed to the mounting surface disposed on the left fixing portion on both the front side and the rear side of the vehicle seat. The first end of the body is arranged to be one of the front end and the rear end of the strain generating body, and the right end on both the front and rear sides of the vehicle seat. In the strain generating body fixed to the mounting surface arranged in the fixing portion, the first end portion of the strain generating body is either one of a front end portion and a rear end portion of the strain generating body. And the first end of the strain generating body disposed on the left fixed portion and the first end of the strain generating body disposed on the right fixing portion. The weight detection sensor of the vehicle seat device according to claim 1, wherein the portion is disposed so as to be in a symmetrical position in the left-right direction. It is.

  The structural feature of the invention according to claim 4 is that, in the strain generating body fixed to the mounting surface disposed on the left fixed portion on the front side of the vehicle seat, a first end of the strain generating body is provided. The mounting portion is disposed so as to be either one of a front end portion and a rear end portion of the strain generating body, and is disposed on the left fixed portion on the rear side of the vehicle seat. In the strain body fixed to a surface, the first end portion of the strain body is disposed so as to be the other end portion of the front end portion and the rear end portion of the strain body, In the strain generating body fixed to the mounting surface disposed on the right fixing portion on the front side of the vehicle seat, the first end portion of the strain generating body includes a front end portion of the strain generating body and The rear end portion is disposed so as to be one of the end portions, and is disposed on the right fixed portion on the rear side of the vehicle seat. In the strain generating body fixed to the abutment surface, the first end portion of the strain generating body is arranged to be either one of the front end portion and the rear end portion of the strain generating body. The weight detection sensor of the vehicle seat device according to claim 3.

  The structural feature of the invention according to claim 5 is that, in the strain generating body fixed to the mounting surface disposed on the left fixing portion on the rear side of the vehicle seat, the first strain generating body is the first. The end portion is disposed so as to be one end portion of the front end portion and the rear end portion of the strain generating body, and is disposed on the right fixed portion on the rear side of the vehicle seat. In the strain generating body fixed to the mounting surface, the first end portion of the strain generating body is arranged to be either one of the front end portion and the rear end portion of the strain generating body. The first end portion of the strain generating body disposed on the left fixed portion and the first end portion of the strain generating body disposed on the right fixing portion are symmetrical in the left-right direction. It is set as the weight detection sensor of the vehicle seat apparatus of Claim 1 arrange | positioned so that it may become a position.

  According to the first aspect of the present invention, the strain detecting element unit has one first end portion (front first end portion on the front side) of the strain body on the mounting surface of the front fixing portion when the weight of the occupant is loaded. ) And the central portion, the first strain detecting element and the third strain detecting element are disposed at a position where the compressive strain is generated, and the second strain detecting element and the fourth strain detecting element are disposed at a position where the tensile strain is generated. The first strain is detected at a position where compressive strain occurs between the other first end (the first end on the rear side) and the central portion of the strain generating body on the mounting surface of the fixed portion on the rear side. The element and the third strain detecting element are arranged, and the second strain detecting element and the fourth strain detecting element are arranged at a position where the tensile strain is generated. The strain detection element units are arranged so as to be paired with at least one of the front and rear and the left and right of the vehicle seat, and the first end portion serving as the pair is in a symmetrical position.

  Thus, since the strain detection element units are arranged in a pair and symmetrically on either the front or rear and left and right sides of the vehicle, the seat side fixing member extending in the front and rear direction with respect to the floor side fixing member is inside. When the relative angular displacement in the direction of tilting is applied, or the relative angular displacement in the direction of twisting in opposite directions around the central axis extending in the left-right direction between the seat side fixing member and the floor side fixing member is one direction When corresponding to each other, the corresponding strain detection elements (for example, the first strain detection elements or the third detection elements corresponding to the first detection elements) in the strain generating body that has become a symmetrical position cause distortion errors in opposite directions. . Thereby, the distortion error can be canceled when adding the detected distortions.

  For example, when the occupant is seated on the seat, the hip point where the occupant's weight is loaded is separated from the position of the floor side fixing member on which the sensor board is disposed, so the seat side fixing that extends in the horizontal direction is left and right. Due to the bending of the member, a load error is generated in each sensor board so as to fall inward in the vehicle width direction. Also in this case, if the strain detection element units are arranged in pairs on the left and right sides of the vehicle and in a symmetrical position, the strain detection elements (for example, the first right-hand side of the strain detection element unit in the symmetrical position) are arranged on the right side. The strain detection element) and the strain detection element arranged on the left side (for example, the first strain detection element on the left side) are subjected to distortion forces so as to fall inside each other in the vehicle width direction. Corresponding strain detection elements generate strain errors in opposite directions. For example, when the first strain detection element on the right side that generates a compressive strain due to a load from the up and down direction of the occupant causes a further compressive strain due to a load error, the first strain detection element on the left side reduces the compressive strain. Therefore, distortion errors generated in the left and right strain detection elements can be canceled.

  In addition, since a large force is generated in the vehicle due to a sudden brake or the like, a relative error that causes a load error in a direction opposite to each other around the central axis extending in the left-right direction between the seat-side fixing member and the floor-side fixing member is generated. When the angular displacement works in one direction, the relative displacement is made between the seat-side fixing member and the floor-side fixing member so that the left and right sides of the vehicle seat are opposite to each other. For this reason, in the strain detection element units arranged at symmetrical positions on the left and right, the strain detection elements arranged on the right side and the strain detection elements arranged on the left side correspond to each other (for example, between the first strain detection elements). ) Causes a distortion error in the reverse direction, so that the distortion error can be canceled in the same manner as described above. Further, in the strain detection element units disposed at symmetrical positions before and after the vehicle seat, the strain detection elements disposed on the front side and the strain detection elements disposed on the rear side correspond to each other (for example, the first Since one strain detection element) generates a distortion error in the reverse direction, the distortion error can be canceled in the same manner as described above.

  According to the invention according to claim 2, in the strain generating body fixed to the mounting surface disposed on the front fixing portion on at least one of the left side and the right side of the vehicle seat, the first end of the strain generating body is: An installation that is arranged to be either one of the front end portion and the rear end portion of the strain generating body, and is arranged on the rear fixing portion on at least one of the left side and the right side of the vehicle seat. In the strain generating body fixed to the surface, the first end portion of the strain generating body is arranged to be either the other end portion of the front end portion or the rear end portion of the strain generating body.

  For example, when the strain detection element unit is arranged at the front end (first end) of the strain generating body at the front fixing portion on the left side of the vehicle seat, the rear fixing portion on the left side of the vehicle seat is raised. The strain detection element unit is disposed at the rear end (first end) of the strain body. Relative angular displacement that causes a load error in the direction of twisting in opposite directions around the central axis extending in the left-right direction between the seat-side fixing member and the floor-side fixing member due to a large force generated in the vehicle by sudden braking, etc. When, for example, on the left side of the vehicle seat, between the front seat side fixing member and the front floor side fixing member, and the rear seat side fixing member and the rear floor side fixing member, The relative angular displacement acting between and in the same direction. However, since distortion in the opposite direction occurs at the first end portion on the front side and the first end portion on the rear side of the strain generating body, the strain detection element (for example, in the strain detection element unit disposed at the first end portion on the front side) The first strain detection element) and the strain detection element (first strain detection element) in the strain detection element unit disposed at the first end on the rear side corresponding to the strain detection element have a distortion error in the opposite direction. To detect. Thereby, the distortion error before and after can be canceled.

  According to the invention of claim 3, in the strain generating body fixed to the mounting surface disposed on the left fixed portion on both the front side and the rear side of the vehicle seat, the first strain generating body The end portion is disposed so as to be one of the front end portion and the rear end portion of the strain generating body, and is connected to the right fixed portion on both the front side and the rear side of the vehicle seat. In the strain body fixed to the mounting surface arranged, the first end portion of the strain body is either one of the front end portion and the rear end portion of the strain body. The first end portion of the strain generating body disposed in the left fixed portion and the first end portion of the strain generating body disposed in the right fixing portion are symmetrical to each other. Arranged to be in position.

  Therefore, when a load error occurs in the direction in which the occupant sits on the seat and falls inward on each sensor board, it is arranged at one of the front end and the rear end of the strain generating body. Since the strain detection element units are arranged at the left and right symmetrical positions of the vehicle seat (for example, the first ends on the left and right rear sides), the corresponding strain detection elements (for example, the first left and right strain detection elements) ) Cause distortion errors in opposite directions. Therefore, the distortion error can be canceled between the left and right strain detecting elements in the strain generating elements disposed on both the front side and the rear side of the vehicle seat.

  In addition, when a large force is generated in the vehicle due to sudden braking or the like, a load error occurs in the direction of twisting in the opposite directions around the central axis extending in the left-right direction between the seat-side fixing member and the floor-side fixing member. The seat side fixing member and the floor side fixing member cause relative angular displacements in opposite directions on the left and right. At this time, in the strain detection element units arranged at symmetrical positions on the left and right, the strain detection elements arranged on the right side and the strain detection elements arranged on the left side correspond to each other (for example, the first left side of the strain detection elements). Since the strain detection element and the first strain detection element on the right side) cause a distortion error in the opposite direction, the distortion error can be canceled in the same manner as described above.

  According to the fourth aspect of the present invention, in the strain body disposed in the left fixed portion on the front side of the vehicle seat, the first end portion of the strain body includes the front end portion and the rear side of the strain body. The first end portion of the strain-generating body is disposed in the right-side fixing portion on the front side of the vehicle seat, and is disposed so as to be either one of the end portions (for example, the front-side end portion). Are arranged to be either one of the front end portion and the rear end portion (for example, the front end portion) of the strain generating body. Therefore, each strain detecting element of the strain detecting element unit disposed at the front end of the strain generating body disposed on the left side of the front side and the front end of the strain generating body disposed on the right side of the front side. For each strain detection element of the strain detection element unit, distortion errors occurring on the front left and right sides between the strain detection elements at symmetrical positions can be canceled.

  In the strain generating body disposed on the left fixed portion on the rear side of the vehicle seat, the first end of the strain generating body is either the front end or the rear end of the strain generating body. In the strain body that is arranged to be an end portion (for example, a rear end portion) and is disposed on the right side fixing portion on the rear side of the vehicle seat, the first end portion of the strain body is the strain body. The front end and the rear end are arranged so as to be one end (for example, the rear end). Therefore, each strain detection element of the strain detection element unit disposed at the rear end of the strain generating body disposed on the left side of the rear side, and the rear end of the strain generating body disposed on the left side of the rear side With respect to each strain detection element of the strain detection element unit arranged in the section, it is possible to cancel a distortion error generated on the left and right sides of the strain detection elements at symmetrical positions.

  In the strain generating body disposed on the left fixed portion on the front side of the vehicle seat, the first end of the strain generating body is one of the end portions of the strain generating body (for example, the front end). The first end portion of the strain generating body is located on the other side of the strain generating body, and is arranged on the rear surface of the vehicle seat and fixed to the mounting surface disposed on the left fixed portion. It arrange | positions so that it may become an edge part (for example, rear edge part). Therefore, each strain detection element of the strain detection element unit disposed at the front end of the strain generating body disposed on the left side of the front side and the rear end of the strain generating body disposed on the left side of the rear side. With respect to each strain detection element of the arranged strain detection element unit, it is possible to cancel a distortion error occurring before and after the left side between the strain detection elements at symmetrical positions.

  In the strain generating body disposed on the right fixed portion on the front side of the vehicle seat, the first end of the strain generating body is arranged to be one end (for example, the front end) of the strain generating body. In the strain generating body fixed to the mounting surface disposed on the right fixing portion on the rear side of the vehicle seat, the first end portion of the strain generating body is the other end portion of the strain generating body (for example, (The rear end). Therefore, each strain detection element of the strain detection element unit disposed at the front end of the strain generating body disposed on the front right side and the rear end of the strain generating body disposed on the rear right side With each strain detection element of the arranged strain detection element unit, it is possible to cancel a distortion error occurring before and after the right side between the strain detection elements at symmetrical positions.

  As described above, in the vehicle seat, the strain detection element units SU are arranged in symmetrical positions at the left and right and the front and rear, so that the left and right rotation between the floor side fixing member and the seat side fixing member. The distortion error due to the relative angular displacement in the direction opposite to each other about the axis and the distortion error due to the relative angular displacement in the direction in which the seat-side fixing member tilts inward due to the seating load are detected in the front and rear and left and right strain detection elements of the vehicle seat. Even in a state in which it works, the distortion error can be canceled.

  According to the fifth aspect of the present invention, in the strain body fixed to the mounting surface disposed on the left-side fixing portion on the rear side of the vehicle seat, the first end portion of the strain body is formed of the strain body. It arrange | positions so that it may become any one edge part of the front edge part and the rear edge part. In the strain generating body fixed to the mounting surface disposed on the right fixing portion on the rear side of the vehicle seat, the first end portion of the strain generating body includes the front end portion and the rear side of the strain generating body. It arrange | positions so that it may become any one edge part of this edge part.

  Therefore, each strain detection element of the strain detection element unit disposed on the front side and one end on the rear side of the strain body disposed on the left side on the rear side, and the strain body disposed on the left side on the rear side Between the strain detection elements of the strain detection element unit arranged at one end of the front side and the rear side of the vehicle, and distortion errors occurring on the left and right sides of the rear side of the vehicle seat between the strain detection elements at symmetrical positions. Can be canceled. And since it is set as the structure which arrange | positions a distortion | strain detection element unit only in two places of the rear side of a vehicle seat, it can aim at reduction of manufacturing cost.

It is a figure showing a 1st embodiment which has arranged a weight detection sensor concerning the present invention in a seat cushion. It is sectional drawing of the weight detection sensor assembled | attached between the seat frame and the upper rail. It is a disassembled perspective view of a weight detection sensor. It is a figure which shows the assembly | attachment state of a weight detection sensor. It is a block diagram which shows a weight detection sensor and a control apparatus. It is a figure which shows the sticking state of each distortion | strain detection element to the strain body of a weight detection sensor. It is a figure which shows another example of the sticking state of each distortion | strain detection element to the strain body of a weight detection sensor. It is a figure which shows the normal deformation | transformation state of the front strain body in FIG. 6A at the time of the load from an up-down direction being loaded with the passenger | crew's weight. It is a figure which shows the normal deformation | transformation state of the back side flexure body in FIG. 6A when the load from an up-down direction is loaded with the passenger | crew's weight. It is a figure which shows the Wheatstone bridge circuit where each distortion | strain detection element was connected as a variable resistance. It is a figure which shows the direction of the load added to a connection member, when a distortion | strain detection element is arranged between the 1st lower bracket and a connection member. It is a figure which shows the direction of the load added to a connection member, when a distortion | strain detection element is arranged between the 2nd bracket and a connection member. It is a figure which shows the relationship between the load added by changing a direction 45 degree | times, and the value as a load error output to a distortion | strain detection element in the state which added the load to the hip point. It is an enlarged view which shows 90 degree | times and 270 degree vicinity in FIG. It is a figure which shows arrangement | positioning of the weight detection sensor and strain detection element unit in 1st Embodiment. It is a figure which shows the state which the connection member of a weight detection sensor falls inward by the bending of the seat frame of the left-right direction. It is a figure which shows the deformation | transformation state of a seat frame when the load biased to the seat frame is loaded. It is a figure which shows the relative angular displacement which the weight detection sensor fixed to the front side and rear side of the left rail and the right upper rail receives. When the weight detection sensor fixed to the rear side on the right side receives a relative angular displacement, the state where the strain body is deformed by the rotational moment load component applied from the connecting member fixed to the seat frame is viewed from the side. It is explanatory drawing. When the weight detection sensor fixed to the rear side on the left side receives a relative angular displacement, a state in which the strain body is deformed by a rotational moment load component applied from a connecting member fixed to the seat frame is viewed from the side. It is explanatory drawing. It is a figure which shows another example which has arrange | positioned the weight detection sensor in four places. It is a figure which shows another example which has arrange | positioned the weight detection sensor in two places on the back side. It is a figure which shows the other another example which has arrange | positioned the weight detection sensor in two places on the back side. It is a figure which shows the arrangement | positioning of the weight detection sensor in 2nd Embodiment, and the state to which force is added when the load biased to the seat frame is loaded. It is a figure which shows the relative angular displacement which the weight detection sensor fixed to the front side and rear side of the left upper rail receives. When the weight detection sensor fixed to the front side of the left upper rail receives a relative angular displacement, a state in which the strain body is deformed by a rotational moment load component applied from a connecting member fixed to the seat frame is viewed from the side. FIG. When the weight detection sensor fixed to the rear side of the left upper rail receives a relative angular displacement, a state in which the strain body is deformed by the rotational moment load component applied from the connecting member fixed to the seat frame from the side. FIG. It is explanatory drawing which shows the state which a strain body deform | transforms by the rotational moment load component which acts on the left-right direction when it receives relative angular displacement in the diagonal direction which inclines from the front-back direction in the front side of the left upper rail. It is explanatory drawing which shows the state which a strain body deform | transforms by the rotational moment load component which acts on the left-right direction when it receives relative angular displacement in the diagonal direction which inclines from the front-back direction in the rear side of the left upper rail. . It is a figure which shows the arrangement | positioning of the weight detection apparatus of 3rd Embodiment, and the state to which force is added when the load biased to the seat frame is loaded. It is a figure which shows arrangement | positioning of the distortion | strain detection element unit of the right upper rail in 3rd Embodiment. It is a figure which shows arrangement | positioning of the distortion | strain detection element unit of the left upper rail. It is a figure which shows the relative angular displacement which the weight detection sensor fixed to the front side and rear side of a right upper rail receives. It is a figure which shows the relative angular displacement which the weight detection sensor fixed to the front side and rear side of the left upper rail receives. It is a figure which shows another example which has arrange | positioned the weight detection sensor in four places. It is a figure which shows arrangement | positioning of the weight detection sensor in a prior art example.

(Example 1)
Hereinafter, a first embodiment of a weight detection sensor 10 of a vehicle seat device according to the present invention will be described with reference to the drawings. In addition, the directions of “front and rear, left and right, and up and down” used in this specification are described with reference to each direction of the vehicle viewed from the occupant seated on the vehicle seat device 100. In the present embodiment, the vehicle is a left-hand drive vehicle, and the presence / absence of a passenger seated in the passenger seat is determined.

  As shown in FIG. 1, a vehicle seat device 100 for a passenger seat is attached to a seat cushion (corresponding to a vehicle seat) 11 on which an occupant is seated and to be rotatable in the front-rear direction at the rear end portion of the seat cushion 11. And a seat back 12 that serves as a backrest for the occupant. A headrest 13 that supports the head of the occupant is attached to the upper end of the seat back 12.

  The seat cushion 11 is formed by a seat frame (corresponding to the seat-side fixing member) 17, a pad member 112 disposed above the seat frame 17, and a skin 113 that covers the surface of the pad member 112. A pair of left and right upper rails (corresponding to a floor side fixing member) 14R and 14L are attached to the lower surface of the seat frame 17. The left front side (corresponding to the front side of the vehicle seat) and the rear side (corresponding to the rear side of the vehicle seat) of the seat frame 17 are provided on the front FL upper surface and the rear RL upper surface of the left upper rail 14L. It is attached via a weight detection sensor (distortion body) described later provided on the surface 18. The right front side (corresponding to the front side of the vehicle seat) and the rear side (corresponding to the front side of the vehicle seat) of the seat frame 17 are connected to the right side by bolts and nuts (not shown) via brackets (not shown). It is attached to the front FR upper surface and the rear RR upper surface of the upper rail 14R. Front left and front sides of the seat frame 17, front upper FL surface (attachment surface 18 (see FIG. 2)) and rear RL upper surface (attachment surface 18) of the left upper rail 14L corresponding to the left front and rear sides. The right front side and the rear side of the seat frame 17, and the front FR upper surface and the rear RR upper surface of the right upper rail 14L corresponding to the right front side and the rear side constitute four fixing portions. The upper rails 14R and 14L are engaged with a pair of lower rails 15R and 15L fixed on the vehicle floor 8 so as to be movable in the front-rear direction. Thus, the vehicle seat device 100 can move in the front-rear direction on the vehicle floor 8 and can be fixed at a position desired by the occupant.

  Next, the weight detection sensor 10 will be described. First, as shown in FIG. 6A, in the strain body 20 arranged before and after the left upper rail 14L, the strain detection described later at the front end (first lower bracket 21a) of the strain body 20 of the front FL. A case where the element unit SU is arranged and a case where the strain detecting element unit SU is arranged at the rear end (second lower bracket 21b) of the strain body 20 of the rear RL will be described.

  The weight detection sensor 10 attached to the upper surface of the front FL of the left upper rail 14L and the weight detection sensor 10 attached to the upper surface of the rear RL differ only in the attachment position of the strain detection element unit SU with respect to the strain body 20. Since the structure is similar, for example, in FIG. 6A, the weight detection sensor 10 attached to the attachment surface 18 on the upper surface of the rear RL of the left upper rail 14L will be mainly described. The weight detection sensor 10 includes a substantially rectangular plate-like strain generating body 20, and first to fourth strain detecting elements SG1 to SG4 attached to the back surface of the strain generating body 20 as shown in FIGS. The first and second lower brackets 21a and 21b for fixing both ends of the strain generating body 20 to the mounting surface 18 of the upper rail 14L so that the strain generating body 20 extends in the front-rear direction, and the center portion of the strain generating body 20 The connecting member 23 fixed to the seat frame 17 in the vertical direction, the upper bracket 24 engaged with both ends of the upper surface of the strain generating body 20, and signals from the strain detecting elements SG1 to SG4. An amplifier board (not shown) to be amplified, an amplifier case 27 in which the amplifier board is accommodated, an FPC (Flexible Printed Circuits) board 28 connected to each of the strain detection elements SG1 to SG4 and the amplifier board, etc. It is composed of

  As shown in FIGS. 3 and 4, the first and second lower brackets 21 a and 21 b are formed at a base portion 29 having a predetermined thickness and projecting from the base portion 29 at both ends of the strain body 20. It comprises a middle shaft portion 31 that is press-fitted into a fixing hole 30 described later, a tip shaft portion 32 that projects from the middle shaft portion 31, and an insertion hole 33 that penetrates through the center.

  Fixing holes 30 are formed at both ends of the strain body 20, and both fixing holes 30 are formed at a predetermined distance that is the same as the interval between the fixing shafts 19 projecting from both ends of the upper rail 14L. As shown in FIG. 4, the strain generating body 20 is press-fitted into the center shaft portion 31 in the fixing hole 30 until the surface abuts against the base portions 29 of the first and second lower brackets 21a and 21b (not press-fitted). In some cases). A central hole 38 is formed in the central portion of the strain body 20, and the central shaft portion 39 of the connecting member 23 is press-fitted into the central hole 38. A flange 40 having a thickness smaller than that of the base portion 29 of the first and second lower brackets 21 a and 21 b is formed at the base end portion of the connecting member 23 and is in contact with the surface of the strain body 20. A front middle shaft portion 41 projects from the end surface of the middle shaft portion (connecting member 23) 39, and a fixing screw portion 42 projects from the end surface of the front middle shaft portion 41. When the front middle shaft portion 41 is press-fitted into the center bracket 48 in a state where the middle shaft portion 39 of the connecting member 23 is press-fitted into the central hole 38 of the strain body 20, the connecting member 23 is connected to the flange 40 and the center bracket 48. The strain body 20 is sandwiched therebetween and fixed to the strain body 20 at the base end portion.

  Moreover, the front-end | tip part of the said connection member 23 is connected with the vehicle seat apparatus 100 as follows. A connecting surface 62 is formed on the back side of the seat frame 17 of the vehicle seat device 100, and a connecting hole 63 is formed in the connecting surface 62 (see FIG. 2). The connecting hole 63 of the seat frame 17 is fitted into the fixing screw portion 42 of the connecting member 23, and the connecting surface 62 is in contact with the upper surface of the center bracket 48. As a result, the seat frame 17 is placed on the upper rail 14 </ b> L via the strain body 20. Then, when the nut 65 screwed to the fixing screw portion 42 is fastened, the connecting surface 62 is pressed against the upper surface of the center bracket 48, and the connecting member 23 of the weight detection sensor 10 is fixed to the seat frame 17.

  Further, as shown in FIG. 3, for example, a steel plate upper bracket 24 is assembled to both ends of the upper surface of the strain body 20. Attachment portions 43 are integrally provided at both ends of the upper bracket 24, and attachment holes 45 are formed in the attachment portions 43 as shown in FIG. These mounting holes 45 are respectively inserted with the front shaft portions 32 of the first and second lower brackets 21 a and 21 b protruding from the upper surface of the strain body 20, and the first and second lower brackets 21 a protruding from the upper bracket 24. , 21b, the washer members 22 are press-fitted into the front shaft portions 32, respectively. As shown in FIG. 3, the upper bracket 24 is formed with an amplifier case mounting portion 47 that integrally connects the mounting portions 43 at both ends so as to extend to the side of the strain body 20.

  The strain body 20 is sandwiched together with the upper bracket 24 between the washer member 22 and the base portion 29 of the first and second lower brackets 21a and 21b at both ends thereof.

  As shown in FIG. 2, the insertion holes 33 of the first and second lower brackets 21a and 21b are fitted to the fixed shaft 19 projecting in the vertical direction at the end of the upper rail 14L, and the base portion The bottom surface of 29 is seated on the mounting surface 18. By tightening the tightening nut 60 screwed into the threaded portion carved at the tip of the fixed shaft 19, the mounting portion 43 of the upper bracket 24 is pressed. As a result, the strain body 20 of the weight detection sensor 10 is fixed at both ends of the mounting surface 18 of the upper rail 14 </ b> L with a predetermined gap corresponding to the thickness of the base portion 29 from the mounting surface 18.

  As described above, the strain body 20 whose central portion is fixed to the seat frame 17 via the connecting member 23 and whose both end portions are fixed to the upper rail 14L has the load of the occupant sitting on the seat cushion 11. When added to the strain body 20 via the connecting member 23, as shown in FIG. 8, both ends thereof are supported by the first and second lower brackets 21a and 21b and bent.

  When this bending occurs, the first lower bracket (corresponding to the first end portion on the front side) 21a and the connecting member (corresponding to the central portion) 23, and the second lower bracket (corresponding to the first end portion on the rear side). ) Between the surface 21b and the connecting member 23, the back surface of the first and second lower brackets 21a and 21b (compression strain is generated on the surface of the strain body 20 in proportion to the load applied by the weight of the occupant. The compressive strain is generated at the position CS), and the tensile strain is generated on the back surface (position TS where the tensile strain is generated) on the connecting member 23 side (see FIGS. 7 and 8).

  In order to detect these distortions, in the strain body 20 attached to the attachment surface 18 of the rear RL, as shown in FIGS. 6A and 8, between the second lower bracket 21b and the connecting member 23, As described above, the first strain detecting element SG1 and the third strain are provided on the second lower bracket 21b side (the position CS where the compressive strain is generated) that generates compressive strain on the back surface of the strain generating body 20 when the weight of the occupant is loaded. The detection element SG3 is attached. Further, between the second lower bracket 21b and the connecting member 23, the connecting member 23 side that generates tensile strain on the back surface of the strain body 20 when the weight of the occupant is loaded (position TS at which tensile strain occurs). The second strain detecting element SG2 and the fourth strain detecting element SG4 are attached to the.

  In the rear RL of the left upper rail 14L, the first strain detection element SG1 and the third strain detection element SG3 are first on the outer side (upper side in FIG. 6A) across the longitudinal center line FRL of the strain body 20. The strain detection element SG1 has a third strain detection element SG3 arranged on the inner side (lower side in FIG. 6A) (corresponding to the opposite side), and the second strain detection element SG2 and the fourth strain detection element SG4 are centered in the front-rear direction. Affixed so that the second strain sensing element SG2 is disposed on the outside (upper side in FIG. 6A) and the fourth strain sensing element SG4 is disposed on the inner side (lower side in FIG. 6A) across the line FRL (corresponding to the opposite side). Is done.

  These first to fourth strain detection elements SG1 to SG4 constitute a strain detection element unit SU. The first to fourth strain detecting elements SG1 to SG4 detect the tensile deformation and compressive deformation in the front-rear direction in which the strain generating body 20 extends as the expansion and contraction of the strain detecting element itself. At the same time, it works as a variable resistance of a Wheatstone bridge circuit, which will be described later, as an electric resistance proportional to expansion and contraction.

  Further, in the strain body 20 attached to the attachment surface 18 of the front FL of the left upper rail 14L, the strain detection element unit SU includes a first end portion (first lower bracket 21a) on the front side and a central portion (connecting member 23). As shown in FIGS. 6A and 7, the first lower bracket 21a side that generates compressive strain on the back surface of the strain generating body 20 when the occupant's weight is loaded (position CS that generates compressive strain). The first strain detecting element SG1 and the third strain detecting element SG3 are attached to the first and second strain detecting elements SG1 and SG3. Moreover, it is between the 1st end part (1st lower bracket 21a) of a front side, and a center part (connecting member 23) (corresponding to the same side), Comprising: When a passenger | crew's weight is loaded, it is the distortion | straining body 20 The second strain detection element SG2 and the fourth strain detection element SG4 are disposed so as to be bonded to the connecting member 23 side where tensile strain occurs on the back surface (position TS where tensile strain occurs).

  Further, as shown in FIG. 9, the first strain detection element SG1 to the fourth strain detection element SG4 constitute a variable resistor of the Wheatstone bridge circuit 50, and the first strain detection element SG1 is the Wheatstone bridge circuit 50. The third strain detecting element SG3 is arranged between the side bd facing the side ac. The second strain detection element SG2 is disposed between the sides bc of the Wheatstone bridge circuit 50, and the fourth strain detection element SG4 is disposed between the sides ad facing the side bc. As a result, a full bridge having the first to fourth strain detection elements SG1 to SG4 as variable resistors is formed on the back surface of the strain body 20 together with the FPC board 28 described later, and is seated on the seat cushion 11 as the strain body 20 is bent. Configured to measure the load of the occupant.

  As shown in FIG. 3, an amplifier case 27 made of, for example, PBT (polybutylene terephthalate) resin is attached to the amplifier case mounting portion 47 of the upper bracket 24 along with the strain body 20 by screws (not shown). Yes. By making the amplifier case 27 made of PBT resin, it is possible to reduce the weight and cost as compared with the conventional aluminum case. The amplifier case 27 is provided with a connector (not shown) for connecting a communication line for transmitting the output of the amplifier board to an electronic control unit (not shown).

  Further, as shown in FIG. 3, the U-shaped FPC board 28 includes a first end portion and a central portion on the front side of the strain generating body 20 at the first to fourth strain detecting elements SG1 to SG4 at the tips of both leg portions. (Or between the rear first end and the center). As described above, these strain detection elements constitute the variable resistance of the Wheatstone bridge circuit 50, and the wiring portion of the FPC board 28 constitutes the wiring connecting the variable resistances of the Wheatstone bridge circuit 50. The U-shaped central portion of the FPC board 28 (corresponding to between ab of the Wheatstone bridge circuit) is connected to the amplifier circuit of the amplifier board.

  Further, as shown in FIG. 5, the weight detection sensor 10 includes a sensor unit 70 including a Wheatstone bridge circuit 50 including first to fourth strain detection elements SG1 to SG4, and a detection generated by the sensor unit 70. And an amplifier 72 for amplifying the signal. The weight detection sensor 10 is connected to a control device 74, and a seat belt wearing detection unit, an airbag display lamp, etc. (not shown) are connected to the control device 74.

  The control device 74 includes an A / D converter 76 that digitally converts an analog detection signal from the weight detection sensor 10, and a calculation unit 78 that inputs the detection signal from the weight detection sensor 10. For example, in the left upper rail 14L, the calculation unit 78 adds the detection value of the weight detection sensor 10 arranged on the front side FL and the detection value of the weight detection sensor 10 arranged on the rear side RL, and calculates the calculated value. After being stored in the storage unit 80, it is transmitted to the seating presence / absence determination unit 82. By various determination processes of the seating presence / absence determination unit 82, for example, the state of “with occupant” and “without occupant” is determined, and the airbag display lamp and the like are controlled.

  The weight detection sensor outputs a positive detection signal when a downward load is applied to the seat cushion 11 due to the seating of an occupant on the vehicle seat device 100, and the upward load is applied to the seat cushion 11. In the case of action, a negative detection signal is output. Note that the weight detection sensors respectively disposed on the front side FL and the rear side RL of the left upper rail 14L are zero-adjusted so that each load value becomes 0 in the vehicle shipment state.

  When the occupant is seated on the vehicle seat device 100 equipped with the weight detection sensor 10 of the present embodiment, the occupant's weight is loaded from above and below, so as shown in FIGS. The portion where the detection element SG1 and the third strain detection element are pasted (the position CS where the compressive strain is generated) undergoes compressive deformation, and the portion where the second strain detection element SG2 and the fourth strain detection element SG4 are pasted ( Tensile deformation occurs at the position TS) where tensile strain occurs.

K: Gauge rate (K = 2), E: Bridge voltage, S1 to S4: Strain of each strain detection element due to the weight of the occupant,
It is known that the voltage e output to the Wheatstone bridge circuit is expressed by the following equation.
e = (E / 4) × K × (S1-S2 + S3-S4)
And a passenger | crew's load is calculated | required based on the voltage e output to a Wheatstone bridge circuit.

(1. Examination and operation of strain detection element unit arrangement when relative angular displacement occurs in the direction of falling inward in the vehicle width direction)
However, when the occupant is seated on the seat cushion 11, the weight of the occupant acts from above and below, but the hip point HP on which the occupant's weight is loaded is the seat frame 17 on which the sensor board (strain body 20) is disposed. Therefore, the seat frame 17 that extends horizontally in the left-right direction of the vehicle is bent. Due to this bending, the seat-side fixing members (members of the seat frame 17 extending in the front-rear direction) corresponding to both ends of the seat frame 17 and the upper rails 14R, 14L are front and rear with respect to the upper rails 14R, 14L. A relative angular displacement occurs in a direction in which the seat frame 17 (and the connecting member 23) extending in the direction falls inward in the vehicle width direction. Therefore, in the strain generating body 20 that detects the occupant's load as a load generated in the vertical direction, a load error in a direction that falls toward the curved left and right seat frame 17 (inside) occurs.
Therefore, the inventors have applied a constant load to the hip point HP of the seat cushion 11, and as shown in FIGS. 10A and 10B, the moment due to the relative angular displacement is applied to the connecting member 23 of the strain generating body 20. The load error detected by the strain detection element unit SU when loaded was measured by changing the direction in which the force is applied every 45 degrees.

The case 1 has a strain detecting element unit SU attached between the first lower bracket 21a and the connecting member 23. The first strain detecting element GS1 and the third strain detecting element GS3 are arranged on the first lower bracket 21a side, and the first strain detecting element SG1 and the third strain detecting element SG3 are arranged before and after the strain generating body 20. It arrange | positions so that it may become the other side on both sides of the direction center line FRL.
The second strain detection element GS2 and the fourth strain detection element GS4 are arranged on the connecting member 23 side, and the second strain detection element SG2 and the fourth strain detection element SG4 are arranged in the front-rear direction center line FRL. It is arranged to be on the opposite side across

The case 2 has a strain detection element unit SU attached between the second lower bracket 21b and the connecting member 23. The first strain detection element GS1 and the third strain detection element GS3 are arranged on the second lower bracket 21a side, and the first strain detection element SG1 and the third strain detection element SG3 are arranged before and after the strain body 20. It arrange | positions so that it may become the other side on both sides of the direction center line FRL.
The second strain detection element GS2 and the fourth strain detection element GS4 are arranged on the connecting member 23 side, and the second strain detection element SG2 and the fourth strain detection element SG4 are arranged in the front-rear direction center line FRL. It is arranged to be on the opposite side across
Then, the front and rear end portions of the strain body 20 were fixed, and a load was applied so as to bend the tip of the connecting member 23 in each predetermined angular direction.

11 and 12 (partially enlarged views in the vicinity of 90 degrees and 270 degrees in FIG. 11) show the relationship between the direction of the force causing the load error and the measured load error. According to this, when a force was applied in the 0 degree (360 degree) direction, a load error of about 55 kg was generated in case 1, whereas a load error of about -55 kg was generated in case 2.
When a force was applied in the direction of 180 degrees, a load error of about −55 kg was generated in case 1, and a load error of about 55 kg was generated in case 2.
When force was applied in the directions of 45 degrees and 315 degrees, Case 1 had a load error of about -38 Kg, whereas Case 1 had a load error of about 38 Kg.
When force was applied in the directions of 135 degrees and 225 degrees, Case 1 had a load error of about -38 Kg, and Case 2 had a load error of about 38 Kg.
Thus, the load error of case 1 and the load error of case 2 show the same numerical value with the positive and negative signs reversed.

  The first strain detecting element SG1 to the fourth strain detecting element SG4 are attached so as to detect the strain in the front-rear direction and do not detect the strain in the left-right direction, but the applied direction is 45 degrees, 135 In degrees, 225 degrees, and 315 degrees, a load error occurs due to a component that causes compression or tension in the front-rear direction. Therefore, the load error should be 0 kg at 90 degrees and 270 degrees, but at 90 degrees, the case 1 is about 4 kg, the case 2 is about -4 kg, the 270 degree is about -4 kg, the case 1 is about -4 kg, Case 2 showed about 4 kg, and a load error occurred where the load error should be zero.

  As described above, as shown in FIG. 14, the seat frame 17 extending in the left-right direction is curved downward and has a seat-side fixing extending in the front-rear direction. It was considered that when the member (seat frame 17) or the connecting member 23 falls inward in the vehicle width direction, the load error that should originally indicate 0 remains as much as the load error in the direction of falling inward.

Therefore, the inventors considered the arrangement of the weight detection sensor 10 and the strain detection element unit SU, as shown in FIG. 13 below, in order to cancel the inward load error due to the seating load.
In the present embodiment, as shown in FIG. 13, the weight detection sensor 10 is configured as follows. The weight detection sensor 10 is disposed on the front side FL of the left upper rail 14L and the front side FR of the right upper rail 14R, and is arranged at the front end (first lower bracket 21a ( The strain detection element units SU are respectively arranged at the front first end portion)). Further, the weight detection sensor 10 is disposed on the rear side RL of the left upper rail 14L and the rear side RR of the right upper rail 14R, and detects strain at the front end (first lower bracket 21a) of the strain body 20 arranged on the left and right. Each element unit SU is arranged. In this way, the strain detection element unit SU is disposed at a position that is symmetrical to the left and right with respect to the center line extending in the front-rear direction of the seat cushion 11.

  In the weight detection sensor 10 of the present embodiment, the seat frame 17 that extends in the left-right direction is curved downward in a convex shape by a seating load, and the seat-side fixing member (seat frame 17) that extends in the front-rear direction is a vehicle. Even in the case of falling inward in the width direction, for example, the strain detection element unit SU of the strain-generating body 20 disposed on the rear RL of the left upper rail 14L of the vehicle seat (seat cushion) 11, and the right upper rail 14R. In the strain detection element unit SU of the strain body 20 disposed on the rear side RR, the left and right strain detection element units SU pass through the center in the left-right direction of the vehicle seat 11 and extend in the front-rear direction (see FIG. (Omitted) is arranged at a symmetrical position. Therefore, as shown in FIG. 14, for example, the rear side of the right upper rail 14R in a symmetrical positional relationship with the first strain detection element SG1 arranged in the strain detection element unit SU on the rear side RL of the left upper rail 14L. Since the first strain detection element SG1 arranged in the strain detection element unit SU of the RR detects a strain error in the opposite direction to each other, the load error due to the inward collapse of the detected connecting member 23 in the vehicle width direction is detected. Can be canceled. Similarly, in the corresponding left and right second strain detecting elements SG2, the left and right third strain detecting elements SG3, and the left and right fourth strain detecting elements SG4 are similarly detected by detecting strain errors in opposite directions. The load error can be canceled. In this way, it is possible to cancel the load error of the detection values of the strain detection element units SU arranged on the left and right.

(2. Operation when relative angular displacement occurs in the direction twisted in the opposite direction)
Further, as shown in FIG. 15, when a biased force that deforms the seat frame 17 due to sudden braking or the like is applied in one direction, the center extending in the left-right direction passes through the center of the seat frame 17 in the front-rear direction. There is a tendency to elastically deform so that the right and left sides of the seat frame 17 are twisted in the opposite directions around the axis OW.

When such a deformation occurs, the weight detection sensor of the present embodiment has a seat frame 17 on the front side FR and the rear side RR of the right upper rail 14R to which the weight detection sensor 10 is attached, as shown in FIG. Relative angular displacements rotating in the same direction (counterclockwise in FIG. 16).
Further, as shown in FIG. 16, the front side FL and the rear side RL of the left upper rail 14L to which the weight detection sensor 10 is attached rotate in the same direction (clockwise in FIG. 16) with the seat frame 17. Relative angular displacement occurs.
Then, a relative displacement in the direction of twisting in opposite directions occurs around the central axis OW extending in the left-right direction between the seat frame 17 along the right upper rail 14R and the seat frame 17 along the left upper rail 14L.

  As a result, as described above, in the rear side RR of the right upper rail 14R in which the counterclockwise relative angular displacement occurs, as shown in FIG. 17, a positive value is generated in the compressive strain when detecting the occupant's load. The second strain detection that generates a positive value in the tensile strain when the compressive strain that causes a positive load error is further detected in the first strain detection element SG1 and the third strain detection element SG3 and the occupant's load is detected. The tensile strain that causes a positive load error is further detected by the element SG2 and the fourth strain detection element SG4.

When applied to the equation of the voltage e output to the Wheatstone bridge circuit for calculating the load, if each strain causing a load error of each strain detection element is Δs1 to Δs4,
e = (E / 4) × K × {(S1 + Δs1) − (S2 + Δs2) + (S3 + Δs3) − (S4 + Δs4)}
When e ₀ = (E / 4) × K × (S1−S2 + S3−S4) and Δe = (E / 4) × K × (Δs1−Δs2 + Δs3−Δs4),
e = e ₀ + Δe.

  Further, when the relative angular displacement described above occurs, in the rear RL of the left upper rail 14L, as shown in FIG. 18, when detecting the occupant's weight, the first strain detection that produces a positive value in the compressive strain. Tensile strain that causes a negative load error is detected in the element SG1 and the third strain detection element SG3, and a negative load is generated in the second strain detection element SG2 and the fourth strain detection element SG4 that generate a positive value in the tensile strain. Compressive distortion that causes an error is detected.

When applied to the equation of the voltage e output to the Wheatstone bridge circuit for calculating the load, if each strain causing a load error of each strain detection element is Δs1 to Δs4,
e = (E / 4) × K × {(S1−Δs1) − (S2−Δs2) + (S3−Δs3) − (S4−Δs4)}
Similarly, when e ₀ = (E / 4) × K × (S1−S2 + S3−S4) and Δe = (E / 4) × K × (Δs1−Δs2 + Δs3−Δs4),
e = e ₀ −Δe.

  Here, the load of the occupant seated on the vehicle seat is obtained by adding the load of the rear RL of the left upper rail 14L and the rear RR of the right upper rail 14R and further doubling the load. When the output voltage (or load value) obtained from the rear RL of the upper rail 14L and the output voltage (or load value) obtained from the rear RR of the right upper rail 14R are summed, the load of the output voltage The error Δe can be canceled.

  Similarly, the strain detection element unit SU of the weight detection sensor 10 provided on the front side FR of the right upper rail 14R and the strain detection element unit SU of the weight detection sensor 10 provided on the front side FL of the left upper rail 14L. In the meantime, it is possible to cancel the distortion error in the case where the relative angular displacement in the direction twisted in the opposite direction occurs.

  As described above, even when the relative angular displacement occurs due to the inward tilt of the seat frame 17 (or the connecting member 23) extending in the front-rear direction due to the seating load, the relative angle in the direction in which the seat frame 17 is twisted in the opposite direction. Even when displacement occurs, the output voltage of the whole body weight detection sensor 10 attached to one vehicle seat 11 by canceling the load error is only based on the vertical strain detected when the occupant is seated. Therefore, the weight of the passenger can be accurately detected.

As is apparent from the above description, according to the weight detection sensor 10 in the present embodiment, when the occupant sits on the vehicle seat (seat cushion) 11, the hip point HP on which the occupant's weight is loaded is the sensor board ( Since the position of the seat frame 17 on which the strain body 20) is disposed is separated, the bending of the seat frame 17 extending in the left-right horizontal direction causes each strain body 20 to tilt inward in the vehicle width direction. Load error occurs. Also in this case, for example, when the strain detection element units SU are arranged in pairs on the left and right sides of the seat cushion 11 and at symmetrical positions, the strain detection elements SG1 disposed on the right side of the strain detection element units SU at the symmetrical positions. Since SG4 and the strain detection elements SG1 to SG4 arranged on the left side are subjected to distortion forces so as to collapse inward in the vehicle width direction, corresponding strain detection elements (for example, in the left and right strain detection element units SU) (for example, Since the first strain detecting elements SG1) generate distortion errors in opposite directions, the distortion errors can be canceled.
When the occupant sits on the seat cushion 11, the seat frame 17 extending in the front-rear horizontal direction is a beam member extending in the front-rear direction because of the high rigidity of the slide rails 14, 15 and the seat frame 17 in the front-rear direction. Almost no bending. For this reason, it is practical to treat the load as if there is no load error in the direction of falling inward in the front-rear direction due to the seating load.

  Further, when a large force is generated in the vehicle due to sudden braking or the like, the pair of seat frames 17 are twisted in the opposite directions around the central axis OW extending in the left-right direction between the seat frame 17 and the upper rail 14. When a relative angular displacement that causes a load error is applied in one direction, a relative angular displacement is generated between the seat frame 17 and the upper rail 14 in opposite directions on the left and right sides of the seat cushion 11. Therefore, in the strain detection element units SG1 to SG4 arranged at symmetrical positions on the left and right of the seat cushion 11, the strain detection elements SG1 to SG4 arranged on the right side and the strain detection elements SG1 to SG4 arranged on the left side correspond to each other. Since the strain detection elements (for example, the first strain detection elements) that perform the same cause a distortion error in the opposite direction, the distortion error can be canceled.

  In the above-described embodiment, the weight detection sensor 10 is disposed on the front and rear sides of the left upper rail 14L, on the front side and rear side of the right upper rail 14R, and on the front ends of the front and rear strain bodies 20 disposed on the left and right. Although the strain detection element unit SU is arranged, the present invention is not limited to this. For example, as shown in FIG. 19, the front and rear strain bodies in which the strain detection element unit SU is arranged on the left and right seat cushions 11 are arranged. It may be arranged at the rear end of 20.

  Further, as shown in FIG. 20, the weight detection sensor 10 (distortion body 20) is arranged on the rear side RL of the left upper rail 14L, the rear side RR of the right upper rail 14R, and the rear side arranged on the left and right. The strain detection element unit SU may be disposed at the front end of the strain generating body 20. Further, as shown in FIG. 21, the weight detection sensor 10 (the strain body 20) is arranged on the rear side RL of the left upper rail 14L, the rear side RR of the right upper rail 14R, and the rear side arranged on the left and right. The strain detection element unit SU may be disposed at the rear end of the strain body 20. 20 and 21, the corresponding strain detection elements (for example, the first strain detection elements SG1) are opposite to each other between the strain detection element units SU arranged at symmetrical positions in the left-right direction. Therefore, the distortion error can be canceled when adding the detected distortions. Further, in this embodiment, since the strain detection element units SU need only be arranged at the two positions on the rear side of the upper rails 14R and 14L, the manufacturing cost can be reduced.

(Example 2)
Next, a second embodiment of the weight detection sensor 10 of the vehicle seat device according to the present invention will be described with reference to the drawings.
In this embodiment, as shown in FIG. 22, the strain detection element unit SU is disposed on the front side of the left upper rail 14L as the first end portion (first lower bracket 21a) on the front side of the strain generating body 20, and the left side. The strain detection element unit SU arranged on the rear side of the upper rail 14L is configured as a first end portion (second lower bracket 21b) on the rear side of the strain generating body 20. The first end portion (first lower bracket 21a) on the front side and the first end portion (second lower bracket 21b) on the rear side have a center line (not shown) crossing the left upper rail 14L in the left-right direction as an axis of symmetry. Is located at a symmetrical position (a symmetrical position in the paired front-rear direction). Since other configurations are the same as those of the first embodiment, the same reference numerals are given and description thereof is omitted.

(Operation when relative angular displacement in the reverse twist direction occurs)
The seat frame (seat-side fixing member) 17 on which the weight detection sensor 10 is disposed is a rectangular rigid body. However, as shown in FIG. 15, there is a biased force that deforms the seat frame 17 by sudden braking or the like. When it works in one direction, it tends to be elastically deformed so that the front side and the rear side of the seat frame 17 are twisted relatively upside down around the central axis OW extending in the front-rear direction.

  When such a deformation occurs, as shown in FIG. 23, the front side FL and the rear side RL of the left upper rail 14L to which the weight detection sensor 10 is attached rotate in the same direction between the seat frame 17. Relative angular displacement occurs.

  Therefore, when the strain detecting element unit SU is arranged on the front end FL (first lower bracket 21a) side of the strain-generating body 20 in the front side FL of the left upper rail 14L, as shown in FIG. Is detected, a tensile strain causing a negative load error is detected in the first strain detecting element SG1 and the third strain detecting element SG3 that generate a positive value in the compressive strain, and a positive value is generated in the tensile strain. The second strain detecting element SG2 and the fourth strain detecting element SG4 detect a compressive strain that causes a negative load error.

In this case, when applied to the equation of the voltage e output to the Wheatstone bridge circuit for calculating the load, if each strain causing a load error of each strain detection element is Δs1 to Δs4,
e = (E / 4) × K × {(S1−Δs1) − (S2−Δs2) + (S3−Δs3) − (S4−Δs4)}
When e ₀ = (E / 4) × K × (S1−S2 + S3−S4) and Δe = (E / 4) × K × (Δs1−Δs2 + Δs3−Δs4),
e = e ₀ −Δe.

  Further, when the strain detection element unit SU is disposed on the rear end RL of the left upper rail 14L on the first end portion (second lower bracket 21b) on the rear side of the strain generating body 20, as shown in FIG. When detecting the body weight, the first strain detecting element SG1 and the third strain detecting element SG3 that generate a positive value in the compressive strain further detect the compressive strain that causes a positive load error, and the tensile strain is positive. The tensile strain causing a positive load error is further detected by the second strain detecting element SG2 and the fourth strain detecting element SG4 that generate values.

In this case, when applied to the equation of the voltage e output to the Wheatstone bridge circuit for calculating the load, if each strain causing a load error of each strain detection element is Δs1 to Δs4,
e = (E / 4) × K × {(S1 + Δs1) − (S2 + Δs2) + (S3 + Δs3) − (S4 + Δs4)}
Similarly, when e ₀ = (E / 4) × K × (S1−S2 + S3−S4) and Δe = (E / 4) × K × (Δs1−Δs2 + Δs3−Δs4),
e = e ₀ + Δe.

Here, the load of the occupant seated on the vehicle seat is obtained by adding the load on the front FL and the load on the rear RL of the left upper rail 14L and further doubling the load.
Therefore, the load error Δe can be canceled when the output voltage (or load value) obtained at the front side FL and the output voltage (or load value) obtained at the rear side RL are summed.

  As apparent from the above description, the weight detection sensor 10 of the present embodiment is the strain generating body 20 that is fixed to the mounting surface 18 that is fixed to the fixing surface 18 disposed on the front FL fixing portion of the left upper rail 14L. The first end portion (first lower bracket 21a) is arranged to be the front end portion of the strain body 20, and is fixed to the mounting surface 18 disposed on the fixing portion of the rear RL of the left upper rail 14L. In the strain generating body 20, the first end portion (second lower bracket 21 b) of the strain generating body is arranged to be the rear end portion of the strain generating body 20 (symmetric in the paired front-rear direction). Is placed in position).

  As described above, when the strain detection element unit SU is arranged at the front end (first lower bracket 21a) of the strain-generating body 20 at the fixing portion of the front FL of the left upper rail 14L, the rear side of the left upper rail 16L In the RL fixing portion, the strain detection element unit SU is disposed at the rear end portion (second lower bracket 21b).

  Therefore, when a large force is generated in the vehicle by sudden braking or the like, a relative angular displacement that causes a load error in the direction of twisting around the rotation axis in the left-right direction acts between the seat frame 17 and the upper rail 14L in one direction. For example, in the left upper rail 14L, the relative angular displacements acting between the seat frame 17 and the front FL upper rail 14L and between the seat frame 17 and the rear RL upper rail 14L are in the same direction (FIG. 23). However, since the first end portion (first lower bracket 21a) on the front side of the strain generating body 20 and the first end portion (second lower bracket 21b) on the rear side are distorted in opposite directions (FIGS. 24 and 25). See), a strain detection element (e.g., a first strain detection element) in the strain detection element unit SU disposed at the first end portion on the front side, and a first end portion on the rear side corresponding to the strain detection element. The strain detection element (first strain detection element) in the strain detection element unit SU detects a strain error in the reverse direction. Thereby, the distortion error before and after can be canceled.

  In this manner, in the strain detection element units SU arranged at symmetrical positions before and after the one-side upper rail 14L, the strain detection elements SG1 to SG4 arranged on the front side FL and the strain detection elements SG1 to SG4 arranged on the rear side RL. Means that the corresponding strain detection elements (for example, the first strain detection elements) cause a distortion error in the opposite direction, so that the distortion error can be canceled.

  In the above-described embodiment, in the left upper rail 14L, the first end portion (first lower bracket 21a) on the front side of the strain-generating body 20 disposed on the front side, and the back of the strain body 20 disposed on the rear side. The strain detection element unit SU is arranged on the first end portion (second lower bracket 21b) side of the side, but is not limited to this. For example, as shown in FIG. 6B, in the left upper rail 14L The rear end portion (second lower bracket 21b) of the strain generating body 20 disposed on the front side FL and the front end portion (first lower bracket 21a) of the strain generating body 20 disposed on the rear side RL. The strain detection element unit SU may be disposed on the side.

  In addition, the strain detection element unit SU is disposed between the first lower bracket 21a and the connecting member 23 in the front side FL strain body 20 of the left upper rail 14L, and in the rear side RL strain body 20 2 between the lower bracket 21b and the connecting member 23. The strain detecting element unit SU is connected to the right upper rail 14R, and the second lower bracket 21b and the connecting member are connected to the strain body 20 on the front FR of the right upper rail 14R. 23, and may be disposed between the first lower bracket 21a and the connecting member 23 in the strain body 20 of the rear RR.

  The first strain detection element SG1 and the third strain detection element SG3 on the mounting surface 18 of the front side FL of the left upper rail 14 are arranged on the opposite sides of the strain body 20 around the center line FRL in the front-rear direction. The second strain detecting element SG2 and the fourth strain detecting element SG4 are arranged on the strain generating body 20 on the opposite sides with respect to the center line FRL in the front-rear direction. The first strain detecting element SG1 and the third strain detecting element SG3 on the mounting surface 18 of the rear RL of the left upper rail 14 are arranged on the opposite sides of the strain generating body 20 around the center line FRL in the front-rear direction. The second strain detection element SG2 and the fourth strain detection element SG4 are arranged on the opposite sides of the strain generating body 20 around the center line FRL in the front-rear direction.

  Therefore, for the distortion caused by the relative angular displacement that affects the left and right direction in the direction in which the rotational angular displacement is not strictly the longitudinal direction of the vehicle but is inclined from the longitudinal direction, for example, as shown in FIG. When compressive strain is detected by the first strain detecting element SG1 and the second strain detecting element SG2 on the front side FL of the upper rail 14L, as shown in FIG. 27, the first strain detecting element SG1 and the first strain detecting element SG1 on the rear side RL of the left upper rail 14L are shown. The two strain detection element SG2 detects tensile strain. At that time, the tensile strain is detected by the third strain detecting element SG3 and the fourth strain detecting element SG4 on the front side FL, and the compressive strain is detected by the third strain detecting element SG3 and the fourth strain detecting element SG4 on the rear side RL. To do. Therefore, the output voltage value corresponding to the load error detected from the strain detection element units SU of the front and rear FL, RL (or the load value obtained based on the output voltage) is output as a value with the opposite sign. It is canceled when the output values of the front and rear weight detection sensors are added together.

Example 3
Next, a third embodiment of the weight detection sensor 10 of the vehicle seat device according to the present invention will be described with reference to the drawings.

  In the weight detection sensor of the vehicle seat device of the present embodiment, as shown in FIG. 28, in the strain body 20 fixed to the mounting surface 18 disposed on the fixing portion of the front FL of the left upper rail 14L, the strain detection element The first end portion (first lower bracket 21a) of the strain body 20 in which the unit SU is arranged is arranged to be the front end portion of the strain body 20, and the rear RL of the left upper rail 14L is fixed. In the strain body 20 fixed to the mounting surface 18 disposed in the section, the first end portion (second lower bracket 21b) of the strain body 20 in which the strain detection element unit SU is disposed is the strain body 20. It arrange | positions so that it may become an edge part of the back side (refer FIG. 28B).

  Further, in the strain generating body 20 fixed to the mounting surface 18 disposed in the fixing portion of the front FR of the right upper rail 14R, the first end (first) of the strain generating body 20 in which the strain detecting element unit SU is disposed. The lower bracket 21a) is disposed at the front end of the strain body 20, and is fixed to the mounting surface 18 disposed on the fixing portion of the rear RR of the right upper rail 14R. The first end portion (second lower bracket 21b) of the strain body 20 on which the strain detection element unit SU is disposed is arranged to be the rear end portion of the strain body 20 (see FIG. 29A). .

  In the above arrangement, the strain detection element units SU are arranged at symmetrical positions on the front FL and FR and the rear RL and RR of the left and right upper rails 14L and 14R (see FIG. 28). ).

  In this manner, the strain detection element units SU are arranged at four positions that are symmetrical before and after the left and right upper rails 14L and 14R. Since these points are different from those of the first and second embodiments and the other configurations are the same, the same reference numerals are given and description thereof is omitted.

(1. Operation when relative angular displacement occurs in the direction of falling inward in the vehicle width direction)
According to the weight detection sensor in the present embodiment, the strain detection element units SU are arranged at positions symmetrical to the left and right in the front FL and FR and the rear RL and RR of the left and right upper rails 14L and 14R. The first strain detection element SG1 disposed in the strain detection element unit SU on the rear side RL of the left upper rail 14L and the strain detection element unit SU on the rear side RR of the right upper rail 14R having a symmetrical positional relationship. Since the first strain detection element SG1 detects strain errors in opposite directions, the load error due to the inward tilting of the connecting member 23 detected in the vehicle width direction can be canceled. Similarly, in the corresponding left and right second strain detecting elements SG2, the left and right third strain detecting elements SG3, and the left and right fourth strain detecting elements SG4 are similarly detected by detecting strain errors in opposite directions. The load error can be canceled. In this way, it is possible to cancel the load error of the detection values of the strain detection element units SU arranged on the left and right.

  Similarly, the strain detection element unit SU on the front side FL of the left upper rail 14L and the strain detection element unit SU on the front side FR of the right upper rail 14R are similarly loaded with each other on the left and right corresponding strain detection elements SG1 to SG4. The error can be canceled.

(2. Operation when relative angular displacement occurs in the direction twisted in the opposite direction)
According to the weight detection sensor of the present embodiment, since the strain detection element units SU are arranged at symmetrical positions in the left and right upper rails 14L and 14R, for example, on the left side (left upper rail 14L), the strain generating body The first front end portion (first lower bracket 21a) and the rear first end portion (second lower bracket 21b) are distorted in the opposite directions, so the first FL of the front FL of the left upper rail 14L. A strain detecting element (for example, a first strain detecting element) in the strain detecting element unit SU arranged at the end (first lower bracket 21a), and a first rear RL of the left upper rail 14L corresponding to the strain detecting element. The strain detection element (first strain detection element) in the strain detection element unit SU arranged at the end (second lower bracket 21b) detects strain errors in directions opposite to each other. To. As a result, the distortion errors of the front and rear FL and RL in the left upper rail 14L can be canceled. Also on the right side (right upper rail 14R), the distortion errors of the front and rear FR and RR can be canceled.

  Further, in the front FL, FR and the rear RL, RR of the left and right upper rails 14L, 14R, the strain detecting element units SU are arranged at positions symmetrical to the left and right, and the left and right strain detecting element units SU are twisted in opposite directions. Relative angular displacement occurs (see FIGS. 17 and 18). Therefore, for example, the first strain detection element SG1 disposed in the strain detection element unit SU on the rear side RL of the left upper rail 14L and the strain detection element unit SU on the rear side RR of the right upper rail 14R in a symmetrical positional relationship. The first strain detection element SG1 arranged in the first and second strain detection elements detects strain errors in opposite directions. Thereby, the load error can be canceled. Similarly, in the corresponding left and right second strain detecting elements SG2, the left and right third strain detecting elements SG3, and the left and right fourth strain detecting elements SG4 are similarly detected by detecting strain errors in opposite directions. The load error can be canceled. In this way, it is possible to cancel the load error of the detected value of the strain detecting element unit SU arranged on the front FL, FR and the rear RL, RR in the left upper rail 14L and the right upper rail 14R.

  As is apparent from the above description, according to the weight detection sensor of the present embodiment, in the strain body 20 arranged at the fixed portion of the front FL of the left upper rail 14L, the first end portion (the first end of the strain body 20) 1 lower bracket 21a) is arranged to be the front end of the strain-generating body 20, and is the first strain-generating body 20 in the strain-generating body 20 disposed at the fixing portion of the front FR of the right upper rail 14R. The end portion (first lower bracket 21 a) is arranged to be the front end portion of the strain body 20. Therefore, the strain detection elements SG1 to SG4 of the strain detection element unit SU disposed at the front end of the strain generating body 20 disposed on the front FL of the left upper rail 14L and the front FR of the right upper rail 14R are disposed. In the strain detection elements SG1 to SG4 of the strain detection element unit SU arranged at the front end of the generated strain generating body 20, the front left and right FL, FR between the strain detection elements at symmetrical positions in the left and right direction It is possible to cancel the distortion error caused by.

  In the strain body 20 fixed to the mounting surface 18 disposed on the fixing portion of the rear RL of the left upper rail 14L, the first end portion (second lower bracket 21b) of the strain body 20 is the strain body. 20, the first end portion of the strain-generating body 20, which is arranged to be the rear end portion of the right-side upper rail 14 </ b> R and is fixed to the mounting surface 18 disposed on the fixing portion of the rear side RR of the right upper rail 14 </ b> R. The (second lower bracket 21b) is disposed so as to be the rear end of the strain generating body 20. Therefore, the strain detection elements SG1 to SG4 of the strain detection element unit SU arranged at the rear end of the strain generating body 20 arranged on the rear side RL of the left upper rail 14L, and the rear side of the right upper rail 14R Among the strain detection elements SG1 to SG4 of the strain detection element unit SU disposed at the rear end portion of the strain generating body 20 disposed in the RR, the strain detection elements SG1 to SG4 that are symmetric in the left-right direction. Distortion errors occurring in the rear left and right RL and RR can be canceled.

  In the strain generating body 20 arranged in the fixed portion of the front FL of the left upper rail 14L, the first end portion (first lower bracket 21a) of the strain generating body 20 becomes the front end portion of the strain generating body 20. In the strain generating body 20 that is arranged as described above and is arranged at the fixed portion of the rear RL of the left upper rail 14L, the first end portion (second lower bracket 21b) of the strain generating body 20 is located behind the strain generating body 20. It arrange | positions so that it may become an edge part of the side. Therefore, the strain detection elements SG1 to SG4 of the strain detection element unit SU disposed at the front end of the strain generating body 20 disposed on the front FL of the left upper rail 14L and the rear RL of the left upper rail 14L. Among the strain detection elements SG1 to SG4 of the strain detection element unit SU arranged at the rear end of the arranged strain generating body 20, the left side of the strain detection elements SG1 to SG4 that are symmetrical in the front-rear direction. Distortion errors occurring in the front and rear FL and RL can be canceled.

  In the strain generating body 20 arranged in the fixed portion of the front FR of the right upper rail 14R, the first end portion (first lower bracket 21a) of the strain generating body 20 is the front end portion of the strain generating body 20. In the strain generating body 20 that is arranged as described above and is arranged at the fixed portion of the rear RR of the right upper rail 14R, the first end portion (second lower bracket 21b) of the strain generating body 20 is located behind the strain generating body 20. It arrange | positions so that it may become an edge part of the side. Therefore, the strain detection elements SG1 to SG4 of the strain detection element unit SU disposed at the front end of the strain generating body 20 disposed on the front side FR of the right upper rail 14R and the rear side RR of the right upper rail 14R. In each of the strain detection elements SG1 to SG4 of the strain detection element unit SU arranged at the rear end of the arranged strain generating body 20, the right and left front and rear FRs between the strain detection elements that are symmetrical in the front-rear direction, Distortion errors caused by RR can be canceled.

  As described above, the seat frame 17 is tilted inward by the distortion error due to the relative angular displacement in the direction of twisting around the central axis OW extending in the left-right direction between the upper rails 14L and 14R and the seat frame 17 and the seating load. The distortion error can be canceled even when the distortion error due to the relative angular displacement is applied to the front and rear and the left and right of the seat cushion 11.

  In the present embodiment, the strain detection element unit SU is disposed at the front end of the strain body 20 on the front side of each weight detection sensor 10 disposed on the left and right, and on the rear side of each weight detection sensor 10 disposed on the left and right. However, the present invention is not limited to this. For example, as shown in FIG. 31, the weight detection sensor 10 includes the front FL and rear RL of the left upper rail 14L and the right side. The rear rail RR is arranged on the front FR and rear RR of the upper rail 14R, and on the rear end of the front strain body 20 of each weight detection sensor 10 arranged on the left and right, on the rear side of each weight detection sensor 10 arranged on the left and right. The strain detection element unit SU may be disposed at the front end of the strain generating body 20. Also in this embodiment, the strain detection element units SU are arranged at symmetrical positions in the front-rear direction and the left-right direction. Therefore, the corresponding strain detection elements (SG1 to SG4) generate distortion errors in opposite directions between the strain detection element units SU that are symmetrically positioned in the front-rear and left-right directions. Since these distortion errors are canceled when the detected strains are summed, the occupant load can be detected with high accuracy.

  In the present embodiment, the first strain detecting element SG1 and the second strain detecting element SG2 are arranged on the same side with the center line FRL in the front-rear direction as the center, and the third strain detecting element SG3 and the fourth strain detecting element SG4. Is arranged on the opposite side with respect to the first strain detection element SG1 and the second strain detection element SG2 with respect to the center line FRL in the front-rear direction, but is not limited to this, for example, the first strain detection element SG1 and the second strain detection element SG1 The strain detection element SG2 is opposite to each other about the front-rear direction center line FRL, and the third strain detection element SG3 and the fourth strain detection element SG4 are opposite to each other about the front-rear direction center line FRL. It may be arranged.

  Further, in the above embodiment, in order to clarify the correspondence relationship between the strain detection elements SG1 to SG4 when the strain detection element unit SU is in a symmetric position, the strain detection elements are four different types. For example, all of the strain detection elements may be of the same type, and the first strain detection element SG1 and the third strain detection element SG3 are of the same type, and the second strain detection element SG2 and the second strain detection element SG2 The 4-strain detection element SG4 may be the same type.

  Moreover, although each strain detection element SG1-SG4 shall be affixed on the lower surface side surface of the strain body 20, it is not limited to this, For example, each strain detection element SG1 on the upper surface side surface of the strain body 20 ~ SG4 may be attached.

  Further, in assembling the strain generating body 20, the connecting member 23 is fixed to the seat frame 17, and the first and second lower brackets 21a and 21b are fixed to the upper rail 14L. The member may be fixed to the upper rail, and the first and second lower brackets may be fixed to the seat frame.

  Thus, the specific configuration described in the above-described embodiment is merely an example of the present invention, and the present invention is not limited to such a specific configuration. Various embodiments can be adopted without departing from the scope.

  DESCRIPTION OF SYMBOLS 8 ... Vehicle floor, 10 ... Weight detection sensor, 11 ... Vehicle seat (seat cushion), 14L ... Floor side fixing member / slide rail (left upper rail), 14R ... Floor side fixing member / slide rail (right upper rail) , 17 ... Seat side fixing member (seat frame), 18 ... Mounting surface / fixing part, 20 ... Strain body, 21a ... First end (first lower bracket), 21b ... First end (second lower) Bracket), 23 ... Center part (connecting member), 50 ... Wheatstone bridge circuit, 100 ... Vehicle seat, CS ... Position causing compression strain, FL ... Left side / front side (front side of left upper rail), FR ... Right side / front side (Front side of right upper rail), OW ... center axis, RL ... left side / rear side (rear side of left upper rail), RR ... right side / rear side (rear side of right upper rail) ), FRL: longitudinal center line, SG1: first strain detecting element, SG2: second strain detecting element, SG3: third strain detecting element, SG4: fourth strain detecting element, SU: strain detecting element unit, TS: Position where tensile strain occurs.

Claims (5)

Seat-side fixing members for fixing the vehicle seat are provided at fixing portions for fixing the vehicle-side seat to the floor-side fixing member fixed to the vehicle floor at four positions on the front, rear, left and right of the vehicle seat, and are seated on the vehicle seat. A weight detection sensor for a vehicle seat device for measuring a passenger's load,
A predetermined gap is formed from each mounting surface on a mounting surface formed on one of the floor-side fixing member and the seat-side fixing member and disposed on the fixing portion on the front side and the rear side of the vehicle seat. A strain body that extends in the front-rear direction of the vehicle seat and is fixed at both ends,
A connecting member fixed in the vertical direction to the central portion of each strain body and fixed to the other of the floor side fixing member and the seat side fixing member;
When the occupant's weight is loaded, the longitudinal center line of the strain-generating body is located at a position where compressive strain is generated on the surface of the strain-generating body between the first end and the center of the strain-generating body. A first strain detecting element and a third strain detecting element arranged to be opposite to each other across the vehicle, and when the weight of an occupant is loaded, the first end portion and the central portion of the strain body The second strain detecting element and the fourth strain detecting element are arranged to be opposite to each other across the center line in the front-rear direction of the strain generating body at a position where tensile strain is generated on the surface of the strain generating body. And a strain sensing element unit having
The first strain detection element and the third strain detection element are disposed on opposite sides, and the second strain detection element and the fourth strain detection element are disposed on opposite sides, each serving as a variable resistor. A Wheatstone bridge circuit,
The vehicle seat in which the strain detection element unit is arranged in a pair on at least one of the front and rear and the left and right of the vehicle seat, and the first end portion that is the pair is symmetrical in the pairing direction. The weight detection sensor of the device. In the strain generating body fixed to the mounting surface disposed on the front fixed portion on at least one of the left side and the right side of the vehicle seat, the first end of the strain generating body is the strain generating body. Are arranged to be either one of the front end and the rear end,
In the strain generating body fixed to the mounting surface disposed on the rear fixed portion on at least one of the left side and the right side of the vehicle seat, the first end portion of the strain generating body includes the strain generating body. Arranged to be the other end of the front end and the rear end of the body,
The weight detection sensor of the vehicle seat apparatus according to claim 1. In the strain generating body fixed to the mounting surface disposed on the left fixed portion on both the front side and the rear side of the vehicle seat, the first end portion of the strain generating body is formed of the strain generating body. It is arranged to be either one of the front end and the rear end,
In the strain generating body fixed to the mounting surface disposed on the right fixing portion on both the front side and the rear side of the vehicle seat, the first end portion of the strain generating body is formed of the strain generating body. It is arranged to be either one of the front end and the rear end,
The first end portion of the strain generating body disposed on the left fixed portion and the first end portion of the strain generating body disposed on the right fixing portion are symmetrical in the left-right direction. The weight detection sensor of the vehicle seat apparatus according to claim 1, which is arranged to be. In the strain generating body fixed to the mounting surface disposed on the left fixed portion on the front side of the vehicle seat, the first end of the strain generating body includes an end on the front side of the strain generating body and It is arranged to be either one of the rear ends,
In the strain generating body fixed to the mounting surface arranged on the left fixed portion on the rear side of the vehicle seat, the first end portion of the strain generating body is an end portion on the front side of the strain generating body. And arranged to be the other end of the rear end,
In the strain generating body fixed to the mounting surface disposed on the right fixing portion on the front side of the vehicle seat, the first end portion of the strain generating body includes a front end portion of the strain generating body and It is arranged to be either one of the rear ends,
In the strain generating body fixed to the mounting surface disposed on the right fixed portion on the rear side of the vehicle seat, the first end portion of the strain generating body is an end portion on the front side of the strain generating body. And arranged so as to be the other end of the rear end,
The weight detection sensor of the vehicle seat apparatus according to claim 3. In the strain generating body fixed to the mounting surface arranged on the left fixed portion on the rear side of the vehicle seat, the first end portion of the strain generating body is an end portion on the front side of the strain generating body. And arranged to be one of the end portions on the rear side,
In the strain generating body fixed to the mounting surface disposed on the right fixed portion on the rear side of the vehicle seat, the first end portion of the strain generating body is an end portion on the front side of the strain generating body. And arranged to be one of the end portions on the rear side,
The first end portion of the strain generating body disposed on the left fixed portion and the first end portion of the strain generating body disposed on the right fixing portion are symmetrical in the left-right direction. The weight detection sensor of the vehicle seat apparatus according to claim 1, which is arranged to be.

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